This invention relates to combined cycle power plants. More particularly, it relates to a method and apparatus for assessing the thermal performance of individual components of a combined cycle power plant and determining the performance impact of each component on the overall thermal performance of the power plant.
Combined cycle power plants utilize gas turbines as prime movers to generate power. Gas turbine engines operate on the Brayton Cycle thermodynamic principle and typically have high exhaust flows and relatively high exhaust temperatures. Exhaust gases, when directed into a heat recovery boiler (typically referred to as a heat recovery steam generator or HRSG), produce steam that can be used to generate more power by, for example, directing the steam to a steam turbine.
During early phases of power plant design, an engineer typically designs a thermal model of each major component of the power plant. For example, a thermal model of each of a gas turbine, steam turbine, HRSG, condenser, etc., may be built. In addition to designing a thermal model for each of the individual components, an overall thermal model combining individual thermal models may also be designed. This overall thermal model is designed to capture the interaction between the individual component models. It may also be used as a basis for thermal performance guarantees at a reference set of boundary conditions.
Demonstration of power plant performance is typically accomplished by conducting a performance test. As testing conditions are not likely to be identical to reference boundary conditions or conditions at performance guarantee conditions, results obtained at test conditions may have to be corrected to provide a true representation of the plant performance at the reference boundary conditions.
In one approach, test results are corrected using a set of curves generated by executing the overall plant thermal model and varying the boundary conditions one at a time. In the event of a performance shortfall, this approach may provide fairly accurate values for corrected power plant performance. This approach, however, provides no indication as to which component(s) of the power-plant is responsible for the performance shortfall.
In another approach, tools for providing diagnostic information on individual power-plant components may be used. However, these tools fail to address the need for diagnosing the overall performance of the combined cycle power plant.
Thus, there is a need to overcome the above-identified problems.
A system and a method for determining the performance impact of individual power plant components on the overall thermal performance of the power plant by assessing the thermal performance of individual components of the power plant.
Specifically, a plant thermal model is used to itemize the performance of individual equipment/components of a power plant. A thermal model of the power plant is initially designed from original power-plant specification documents. A second thermal model is then developed using measured performance data of individual components of the power plant built in accordance with requirements set forth in the original power-plant specification documents. The performance impact of each component of the power plant on the overall thermal performance of the power plant is then determined by substituting the design thermal performance data of each component with its measured thermal performance data. In this manner, the impact on the overall thermal performance of the power plant is determined by assessing the thermal performance of individual power plant components.
In one aspect, the present invention provides a method of determining performance impact of individual components of a power plant on overall thermal performance of the power plant, the method comprising (a) designing a first thermal model of the power plant using original specification data of the power-plant; (b) developing a second thermal model of the power plant from measured performance data of each component of the power-plant; (c) determining the performance impact of a selected component of the power-plant on the overall thermal performance of the power-plant by substituting design performance data of the selected component in the first thermal model with its measured performance data. Step (c) is repeated until the performance impact of each component of the power plant on the overall thermal performance of the power plant is determined. The method further comprises displaying the performance impact of each component on the overall thermal performance of the power plant. The step of designing a first power plant thermal model further comprises i) receiving original specification data in a computer system; and ii) processing the specification data to design the first thermal model. The step further includes the step of developing a second model including i) measuring performance data of each component of the power-plant using a data acquisition computer; ii) storing measured performance data in the data acquisition computer; iii) receiving the measured performance data from the data acquisition computer in a processor system; and iv) processing data received in the processor system to design the second thermal model.
In another aspect, an apparatus for determining performance impact of individual components of a power plant on overall thermal performance of the power plant, comprises means for designing a first thermal model of the power plant using original specification data of the power plant, means for developing a second thermal model of the power plant from measured performance data of each component of the power plant and means for determining the performance impact of a selected component of the power plant on the overall thermal performance of the power plant by substituting design performance data of the selected component in the first thermal model with its measured performance data. The apparatus further comprises means for repeating the determining step until the performance impact of each component of the power plant on the overall thermal performance of the power plant is determined, and means for displaying the performance impact of each component of the power plant on the overall thermal performance of the power plant. The apparatus also includes a means for receiving original specification data, means for processing the specification data to design the first thermal model. The means for developing the second thermal model further comprises means for measuring the performance of each component of the power plant and means for storing measured performance data. The apparatus further comprises means for receiving the measured performance data and means for processing received data to design the second thermal model.
In a further aspect, a computer program product comprising a computer useable medium having computer program logic stored thereon for enabling a processor in a computer system to process data, the computer program product comprises means for designing a first model using original specification data of a power plant, means for developing a second model from measured performance data of each component of the power plant, and means for determining the performance impact of a selected component of the power plant on the overall thermal performance of the power plant by substituting design performance data of the selected component in the first model with its measured performance data. The computer program product further comprising means for repeating the determining step until the performance impact of each component of the power-plant on the overall thermal performance of the power-plant is determined, means for displaying the performance impact of each component of the power plant on the overall thermal performance of the power plant, means for receiving original specification data, means for processing the specification data to design the first model, means for measuring the performance of each component of the power plant, means for storing measured performance data, means for receiving the stored measured performance data, and means for processing received data to design the second model.
In yet another aspect, a computer-based method for providing assistance to a user of an application program for assessing the performance impact of individual components of a power plant on overall thermal performance of the power-plant, the method comprising the steps of (a) using the application program to design a plant thermal model from original power-plant specification data, (b) using the application program to design a matched thermal plant model from measured performance data of individual components of the power-plant, (c) substituting design performance data of a selected component of the power plant in the plant thermal model with corresponding measured performance data and (d) repeating step (c) for each component of the power plant.
In a further aspect, a computer-readable medium having computer-executable instructions for performing the steps of (a) designing a first thermal model of the power plant using original specification data of the power plant; (b) developing a second thermal model of the power plant from measured performance data of each component of the power plant; and (c) determining the performance impact of a selected component of the power plant on the overall thermal performance of the power plant by substituting design performance data of the selected component in the first thermal model with its measured performance data.